On Tue, Oct 09, 2018 at 03:20:42PM -0700, Joel Fernandes (Google) wrote:
Add tests to verify sealing memfds with the F_SEAL_FS_WRITE works as expected.
Cc: dancol@google.com Cc: minchan@google.com Signed-off-by: Joel Fernandes (Google) joel@joelfernandes.org
tools/testing/selftests/memfd/memfd_test.c | 51 +++++++++++++++++++++- 1 file changed, 50 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index 10baa1652fc2..4bd2b6c87bb4 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -27,7 +27,7 @@ #define MFD_DEF_SIZE 8192 #define STACK_SIZE 65536
+#define F_SEAL_FS_WRITE 0x0010 /*
- Default is not to test hugetlbfs
*/ @@ -170,6 +170,24 @@ static void *mfd_assert_mmap_shared(int fd) return p; } +static void *mfd_fail_mmap_shared(int fd) +{
- void *p;
- p = mmap(NULL,
mfd_def_size,PROT_READ | PROT_WRITE,MAP_SHARED,fd,0);- if (p != MAP_FAILED) {
printf("mmap() didn't fail as expected\n");abort();- }
- return p;
+}
Ah, this function is unused. I wrote it initially and used it but then figured I didn't need it, and then forgot to remove it. It does not affect the correctness of the patch. Anyway below is the updated patch.
thanks,
- Joel
------8<-----
From: "Joel Fernandes (Google)" joel@joelfernandes.org Subject: [PATCH v2.1] selftests/memfd: Add tests for F_SEAL_FS_WRITE seal
Add tests to verify sealing memfds with the F_SEAL_FS_WRITE works as expected.
Cc: dancol@google.com Cc: minchan@kernel.org Signed-off-by: Joel Fernandes (Google) joel@joelfernandes.org --- tools/testing/selftests/memfd/memfd_test.c | 33 +++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index 10baa1652fc2..d074de568ba0 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -27,7 +27,7 @@
#define MFD_DEF_SIZE 8192 #define STACK_SIZE 65536 - +#define F_SEAL_FS_WRITE 0x0010 /* * Default is not to test hugetlbfs */ @@ -692,6 +692,36 @@ static void test_seal_write(void) close(fd); }
+/* + * Test SEAL_WRITE + * Test whether SEAL_WRITE actually prevents modifications. + */ +static void test_seal_fs_write(void) +{ + int fd; + void *p; + + printf("%s SEAL-FS-WRITE\n", memfd_str); + + fd = mfd_assert_new("kern_memfd_seal_fs_write", + mfd_def_size, + MFD_CLOEXEC | MFD_ALLOW_SEALING); + + p = mfd_assert_mmap_shared(fd); + + /* FS_WRITE seal can be added even with existing + * writeable mappings */ + mfd_assert_has_seals(fd, 0); + mfd_assert_add_seals(fd, F_SEAL_FS_WRITE); + mfd_assert_has_seals(fd, F_SEAL_FS_WRITE); + + mfd_assert_read(fd); + mfd_fail_write(fd); + + munmap(p, mfd_def_size); + close(fd); +} + /* * Test SEAL_SHRINK * Test whether SEAL_SHRINK actually prevents shrinking @@ -945,6 +975,7 @@ int main(int argc, char **argv) test_basic();
test_seal_write(); + test_seal_fs_write(); test_seal_shrink(); test_seal_grow(); test_seal_resize();